Organic light-emitting diodes (OLEDs) have the characteristics of wide color gamut, high contrast, energy saving, and fold-ability, and thus have a strong competitiveness in new generation's displays. Among them, active-matrix organic light-emitting diode (AMOLED) technology is one of the key development directions for flexible displays. The basic driving circuit of AMOLED is shown in FIG. 1, which belongs to the 2T1C mode including two thin film transistors and one storage capacitor. Specifically, it includes a switching thin film transistor A1, a driving thin film transistor A2, and a storage capacitor C1. The driving current of OLED is controlled by the driving thin film transistor A2, and has the current size of IOLED=k(Vgs−Vth)2, where k is a current amplification factor of the driving thin film transistor A2, which is determined by the characteristic of the driving thin film transistor A2 itself, and Vth is a threshold voltage of the driving thin film transistor A2. The threshold voltage Vth of the driving thin film transistor A2 may shift due to long operation time, which results in the change in the driving current of OLED, and may cause defects in OLED panel and affect the image quality.